Well Killing Method (Circulation Method)

Well Killing Method (Circulation Method)

The Circulation Method (specifically the Circulation and Weight-up Method - sometimes referred as the Weight-up on the Fly Method) is one of the commonly applied methods for well killing. In this article, we'll walk you through the process, including the calculations, the steps involved and best practices for successful implementation.

How Well Killing Works by Circulation Method

Circulation Method: Applied when a well in the uncontrolled influx of formation fluids. The aim is to flow out the inflow and to displace the drilling fluid with a kill mud that has a higher density to reassume control on the wellhead. This method minimizes pressure fluctuations, thereby mitigating the likelihood of secondary kicks or wellbore instability.

Weight-up on the Fly Method (Circulation and Weight-up Method)

In this technique, influx fluid and drilling fluid densities are gradually raised together83. Its usage is a standard in circumstances demanding controlled pressure management input.

Step-by-Step Procedure

Step 1: Properly Shut-in the Well

When flow is observed at the surface, the well should be promptly killed using the blowout preventer (BOP) system.

Write down the following key parameters:

Internal Wash Pipe Pressure (IWPP)

Shut-In Casing Pressure (SICP)

Pit Gain (for estimating inflow volume)

The applied pressures are recorded and further used in calculations.

2: Start Circulation and Hit the Weight-up

Pre-arranged schedule to start circulating the well.

Gradually increasing the density of the kill mud to prevent rapid changes in the system that may lead to pressure surges.

Pressure Calculation and Pump Strokes

To successfully implement the Circulation and Weight-up Method, it واجب to perform The following calculations:

Calculation of the pressure drop in the standpipe

Establish the standpipe pressure drop associated with each incremental change in kill mud density (e.g., for every 0.01 g/cm³ increase).

Calculating the Initial Circulating Pressure (ICP)

The Invasion Column Pressure (ICP) is determined from original drilling fluid density and recorded pressures.

Pump Strokes Calculation

Determine the number of pump strokes to circulate the kill mud from surface to bottom of the work string.

Computing the Final Circulating Pressure (FCP)

Standpipe pressure must be held at the final circulating pressure calculated, when the kill mud in the stand pipe is definitely reached final density and when it completely fills the drill pipe.

Fluid Incremental Density Schedule and Pressure Control

As a result, maintain a good control of the standpipe pressure throughout the operation, to avoid big swings in pressure that might result in secondary kicks.

FINAL STEP: Execute the Killing Operation

Maintain a constant standpipe pressure once drill pipe has filled with kill mud of the final target density.

Sweeping in the annular area (use the amount of returns to find the area filled with kill mud).

Make sure to fully circulate the influx fluid out of the system.

Allocate truck time for monitoring pressures and fluid levels to observe the stability of the well.

The killing operation is accomplished with the well in a static, controlled state.

How to Use the Circulation and Weight-up Method

Pressure Management Explained

The slow density evolution creates no sudden ramp-ups, which would help for further inflow or collapse.

Reduced Risk of Second Kicks

Optimizing standpipe pressure helps to minimize secondary kicks and optimize secondary pressure with the use of careful monitoring.

Making the Best Use of Time and Resources

This not only decreases the overall well control time but also expedites the procedure.

Improved Wellbore Stability

In addition to economic benefits, the disrupting technology minimises pressure swings that may cause instability in the wellbore and formation damage.

As they say, the devil is in the details.

Monitor Drill Pipe and Casing Pressures: By providing continuous monitoring of drill pipe and casing pressures, any abnormalities will be detected early and corrective action taken.

Application of real-time data analysis: In the contemporary drilling system, well control system is tracking the data in real time and helps in better decision making during the operation.

Clear Communication: Close collaboration and communication between rig crew, drilling engineers and well control specialists are crucial for seamless implementation.

Routine Training and Drills: Performing well control drills gets the crew prepared for emergencies, minimizing response time when actual well control incidents occur.

Frequent Issues and Their Solutions

Drill into the wall: incompressible fluid rotates around wellbore

Solution: Plan the schedule for density increment cautiously and implement it stepwise to prevent abrupt pressure transitions.

Problem: Final Circulating Pressure (FCP) The FCP is the pressure at which the mill accommodates the gas circulation. The FCP is calculated as the difference between the Circulating Pressure (CP) and the operating assumption of the gas circulation.

Solution: Make sure that calculations are double checked and all the parameters are accurately taken into account before implementation.

Problem: Exploiting the Overpressure

Solution: Pump at pump rates that will not lead to losses and maintain a constant standpipe pressure.

Conclusion

It also presents a highly efficient well control technique called the Circulation and Weight-up Method which safely and expertly helps to manage influx. Narrate: Carefully following a structured methodology, accurately computing with best practices will be able to carry out with minimum risk the well control operation. The successful execution of this process relies heavily on adequate training, real-time monitoring, and clear communication.

FOPENGG: Fundamentals of Petroleum Engineering, to learn more about well control methods, drilling techniques and trends in the oil industry.